Holbein - Acryla Gouache - 20 ml - Metallic Yellow - Acryla Gouache is an ideal medium available to the artist, designer, illustrator and student. Acryla Gouache has 102 highly pigmented colors, including 10 metallic and 4 luminous finishes, in an acryl resin which will dry to the same smooth mat finish as does the Holbein DesignersÆ Gouache in gum arabic.